Fig. 57. Bruneseau visiting the old Paris sewers.
Fig. 58. Junction of old Paris sewers. From Hugo's "Les Miserables."
Fig. 58 gives the point of junction of several of these old sewers, described by Hugo as "winding, cracked, un-paved, full of pits, broken by strange elbows, ascending and descending illogically, fetid, savage, ferocious, submerged in darkness, with gashes on its stones and scars on its walls."
The various methods of sewage purification now in operation in various parts of the world have shown the water carriage system of disposal to be far in advance of any dry system.
Erwin F. Smith in his treatise on "The Influence of Sewerage and Water Supply on the Death Rate in Cities," read at the sanitary convention in Michigan, July, 1885,* shows by charts I, II and III the reduction of the death rate of cities occasioned by the introduction of sewerage systems, and in spite of their antiquity they form as powerful arguments in favor of good sewerage as can be found.
His conclusions are:
(1) Typhoid fever and cholera decrease in proportion as a city is well sewered.
(2) There is no direct relation between diphtheria and sewers.
(3) The general death rate falls after the sewering of a city, and, other things being equal, never again reaches the maximum of its anti-sewered condition.
(4) The cost of building and maintaining sanitary works is inconsiderable, in comparison with the direct pecuniary loss, by sickness and death, which their absence entails.
*Reprinted from Supplement to Annual Report Michigan State Board of Health.
Approximate Estimate of the Comparative Average
Cost of Plumbing Work Under the Present
Complicated and the New Simple System
(1) The back venting of traps should be prohibited. In estimating the saving which would come from this item we find that no close figure can be given without making a very extensive study of the different conditions involved, aided by exhaustive statistics. Very high buildings would require, for effective back venting such an increase of size of pipe for each additional story to overcome friction, that the cost of the back vent pipes would far exceed that of the waste pipes. In buildings of the average height the cost should about equa that of the waste pipes. We may take Figs 264 and 265 for fair examples of the two methods of piping for such buildings, except that in Fig. 264 the back vent pipes have not been sufficiently enlarged in the upper stories. (See Chap. XLIV.)
(2) Flexible joints and "Standard" thickness of pipes should be substituted for lead caulked and rigid joints with "Extra heavy" thickness. "Standard" thick cast-iron pipes weigh about half as much as "Extra heavy," and the cost of the former, considering the comparatively high cost of hand caulking is less than half that of the latter. See Note on pages 694 and 695.
(3) The use of the main house trap and its foot vents and other piping involved should be prohibited. The percentage of saving in this item depends upon the amount of piping which would be considered by different persons as necessitated by the use of this disconnecting trap. It would sometimes amount to a very large sum.
(4) The law calling for separate traps under each of several connecting fixtures should be modified. This would also sometimes amount to quite a large percentage, especially where back venting is difficult.
(5) The law requiring water closet rooms to be ventilated by special air shafts lighted by external windows should be modified to permit of their ventilation through effective ventilating pipes or ducts. This requirement sometimes involves the loss of exceedingly valuable room and outer wall space without any advantage, as explained in detail on pages 595 to 598, and the average saving possible in this item runs up to a very high figure.
(6) The law forbidding soil pipes to serve also as rain water conductors should be changed where the combined system of sewerage is used. This would there save one or more stacks of large oipes from roof to basement.
(7) The use of the hydraulic test for piping should be prohibited, because, while very expensive and altogether useless, it puts a strain on the piping far beyond what could ever be encountered in practice, and which, like excessive boiler pressure tests, for instance, may result either in destroying the property at once, or in developing unseen defects liable to appear disastrously in the future.
Taking all these large items together, and several smaller ones not here mentioned, the author believes the relative costs of the two systems of plumbing may be fairly represented by the comparative sizes of the squares shown in our initial cut. (See Chap. XLIV.)
Simple System in Alterations